1. Field of the Invention
The present invention relates generally to hand tools and more particularly a device for stripping the insulation cover from an insulated wire such as those normally employed for transmitting electrical energy in a building with an improved ergonomic function. More particularly, the present invention relates to an electrical installer hand tool having a convenient and easy to use wire stripping mechanism for stripping an insulation layer from a wire during use of the hand tool that provides for an improved stripping-motion by a user and results in reduced hand and forearm stress and correspondingly to reduced risk of long term injury through repetitive use created by common wire stripping systems.
2. Description of the Related Art
Electricians, among others, typically require a number of tools for assisting in the various operations they normally conduct in the ordinary course of business. One of the tools normally required by an electrician is a screwdriver. Also, the electrician normally employs some type of tool, typically a scissor-action type hand tool operably provided with two handles and a crossed pivot point, for aiding in the removal of insulation from an end portion of an insulated wire for enabling the wire to be connected to a terminal post or the like. An electrical wire generally comprises an inner core of conductor that is surrounded by an insulation layer. When the electrical wire is joined to other wires or connected to a terminal, the insulation needs to be removed. The purpose of a wire stripping apparatus is to remove the insulation from around the core of the wire to expose the core of the wire.
Wire strippers or wire stripping devices are used by electricians and other professionals to separate a short segment of insulation from a wire to expose the underlying conducting wire for making connections. For small gauge wires, a wire stripping pliers, utility knife, or other hand tool may typically be used. For larger gauge wires, where the insulation layer is typically thicker and more rigid, it is more difficult to remove with hand tools. Unfortunately, damage may be caused to the underlying conductor when penetrating the insulation layer with a manual cutting tool (such as a wire cutter or knife) due to imprecise cutting depth control. Rather elaborate tools have been previously provided for stripping the insulation from the wire, but these tools can be relatively expensive and have only the single purpose of removing insulation. Thus, such tools are burdensome to carry and occupy a considerable space area within the tool box or wherever it is carried. Additionally, these tools are commonly such scissor-action types as noted in FIG. 1. Unfortunately such scissor-action types require a user to pull against the axis of the wire to strip the outer insulation and this creates a stress on a user's forearm, wrist, hand, and even upper arm. Typically, after much stripping (by a professional installer) a sort of wire-strippers-elbow can result from damage to the wrist and elbow muscles, ligaments, and tendons due to the constant outwardly stress. Even worse, should a user flex their wrist (not maintain a rigid wrist aligned with the forearm) then carpal tunnel syndrome can occur. References to such stresses, and the damages to the same, can be found discussed in “Finger Force Capability: Measurement and Prediction Using Anthropometric and Myoelectric Measures”; Angela D. Astin, a thesis, Virginia Polytechnic Institute and State University, Dec. 16, 1999, the entire contents of which are incorporated herein by reference.
Also, other known wire stripping devices include the type comprising a pair of V-shaped cutters that are provided opposite to an insulated wire and blades of the cutters are moved toward the insulated wire to cut into the insulation from opposite sides without damaging the core, and the cutters are caused to move in the lengthwise direction of the wire to remove the insulation. According to this type of stripper in which the blades are caused to move in the length of the wire, if cross sectional shapes of wire and/or core are not uniform in the lengthwise direction of wire or if an adhesion between the core and the insulation is strong, it may be difficult to strip the insulation from the wire properly. Moving the blades cutting into the insulation along the lengthwise direction of the wire may result in damage to the core.
Another type of wire stripping device relates to an assisting tool for wire stripping in which a cut is formed in the insulation by using heated blades. In stripping the insulation using this tool, a separate process is required to pull out the insulation from an end of the wire. It is difficult to pull the insulation if the length of the insulation to be removed is short. It is also difficult to twist strands of the core by pulling out the insulation to keep the strands together.
Also known as wire stripping (and cutting) tools are wire stripping knives, generally for the stripping of the outer insulation of a wire from the core portion. Such a wire stripping knife has blade and handle members with the handle member having a forward and rearward portion as well as a base surface. In such a tool, a stripping mechanism is attached to the handle and has both open and closed orientations. The stripping mechanism has an inward surface operatively configured to engage the wire to be stripped where the inward surface of the stripping mechanism cooperates with the base surface of the handle such that when in a closed orientation, either the inward surface or the base surface incises the insulation of the wire from the core portion.
Wire strippers or wire stripping tools have been around since the use of insulation began. One such tool uses a pivoting handle to operate a pair of jaws. The jaws have a wire cutter and a series of cutters designed to fit around and clamp through the insulation of a specific size wire, but not cut the wire itself. Retelling to FIGS. 1-3, shown is a typical prior art wire stripping tool 100. As shown, this tool 100 has a cutting head 101, and a pair of handles 102 connected by a pivot assembly 103. The tool 100 is used by opening and closing the handles 102 to activate the cutting head 101. The cutting head 101 has a pair of jaws which act as a crimper or pliers jaw 105. Below that is a series of upper and lower cutting jaws 106 for stripping the wire 121. These jaws are used to strip the insulation off wire 121, and each cutting jaw 106 is sized for a different wire gauge. At the bottom of the cutting head 101 are two holes 120 that can be used for bending wires.
Accordingly, this invention now recognizes that there is a need for a wire stripping assembly incorporated into the handle of a screwdriver or other multi-function tool whereby the tool will be effective for its normal uses and operations and includes a wire stripping mechanism that adds very little to the weight and bulkiness of the tool and which facilitates easy and effective stripping of the insulation from a wire while eliminating damages to a core.